Does Diving Make You Daft?

As we age, we become more aware of our lack of mental capacity, especially when it comes to short-term memory. Do we have difficulty recalling things because we simply have too much information stored? Are the hard drives of our brains so full it takes more time to search out individual items, or are we simply losing our minds? Or, has too much diving damaged our brains?

Dr. Christian Seiler, of the University of Berne, scanned the brains of 52 divers who had completed at least 200 dives and compared them with those from the same number of healthy adults who had never scuba dived.

The research showed 41 lesions in 19 of the divers compared with seven lesions in six of the non-divers. His conclusion was that diving increased the incidence of one or more brain lesions five fold.

The affected divers had not performed a greater number of dives nor at a deeper depth than the unaffected divers, and the lesions did not appear to be linked to other causes. Nor did the study suggest that these brain lesions occurred in divers who had suffered symptoms of decompression sickness, although the study, published in the Annals of Internal Medicine, confirmed fears that they were more common in divers who have a PFO (patent foramen ovale).

We asked Petar Denoble of DAN for a comment on this, but although he had not seen the paper in question, he pointed us to another paper; Long-Term Neurologic Damage and Brain Lesions in Recreational Divers by Michael Knauth of the University of Medicine, Goettingen, Germany. It reviews other research done in Norway, the USA, Germany and Switzerland and highlights that while divers had significantly more brain lesions than the non-divers, there was also a correlation between the presence of a PFO and brain lesions.

"That the number of brain lesions was also increased in the group of divers without PFO suggests that there are also other mechanisms for the origin of brain lesions in divers besides PFO."

This is the conclusion in full:

"Long-term neurologic damage in the form of neuropsychological performance or brain lesions should neither be dramatized nor played down. Brain lesions have so far not been linked with a reduction in neuropsychological performance, and the neuropsychological impairment in divers in the Swiss study occurred in relation to quite extreme diving behavior.

On the other hand, recreational diving is a leisure activity, and the brain is the organ to which we owe our mental capacity and our personality. As in other areas of life, the same should apply to diving: moderation in all things. In any case, there is so far no evidence of longterm neurologic damage in the form of reduction of cerebral capacity with moderate recreational diving."